Cloud types

Clouds
Discussion

I. Classification
II. Definition and clouds type photographs
III. Causing the phenomena




I. Classification:

Extreme-level: Nacreous, Noctilucent
High-level: Cirrus (Ci), Cirrostratus (Cs) Cirrocumulus (Cc), Contrail
Medium-level: Altostratus (As), Altocumulus (Ac),  Nimbostratus (Ns)
Low-level: · Stratus (St), Stratocumulus (Sc) Cumulus (Cu)
Vertical: Cumulonimbus (Cb)

A. Low-level
Stratus: Stratus means layer or blanket in Latin. A stratus cloud (St) is a cloud belonging to a class characterized by horizontal layering with a uniform base.

II. Definition and clouds type photographs
Stratus Clouds
This type of stratus cloud forms in mountainous areas.
Image courtesy of Olga and Sergei Kuznetsov
Stratus Clouds
This image of stratus clouds was taken at sunrise in eastern Colorado. Stratus clouds usually cover the entire sky.
Image courtesy of Gregory Thompson

B. Medium-level
Altostratus (As): is a cloud belonging to a class characterized by a generally uniform gray sheet or layer, lighter in color than nimbostratus and darker than cirrostratus.
Altostratus Clouds
This image of altostratus clouds was taken in Boulder, Colorado.
Image courtesy of Carlye Calvin
Altostratus

2. Altocumulus (Ac): Altocumulus (Alto, "middle", cumulus, "heaped") is a cloud belonging to a class characterized by globular masses or rolls in layers or patches, the individual elements being larger and darker than those of cirrocumulus and smaller than those of stratocumulus.
Altocumulus Clouds
Occasionally altocumulus clouds show vertical development and produce tower-like extensions. These altocumulus clouds are in the early stages of development.
Image courtesy of the UCAR Digital Image Library
Altocumulus Clouds
Sometimes altocumulus clouds appear as white or gray puffy masses in ripples or waves.
Image courtesy of Peggy LeMone

Altocumulus Clouds
Photo of altocumulus clouds at sunset
Image courtesy of Peggy LeMone
3. Nimbostratus (Ns): is a cloud characterized by a formless cloud layer that is almost uniformly dark gray.

Nimbostratus Clouds
Nimbostratus clouds are dark gray with a ragged base.
Image courtesy of English Wikipedia
Nimbostratus Clouds
This image of nimbostratus clouds was taken in Seattle, WA. Notice the rain falling out of the clouds, as well as the rainbow!
Image courtesy of Peggy LeMone
C. High-level
Cirrus (Ci): are clouds composed entirely of ice and consist of long, thin, wispy streamers. They are commonly known as "mare`s tails" because of their appearance.
Cirrus Clouds
Cirrus clouds may appear even over some of the world`s driest areas, such as the high Atacama Desert of northern Chile.
Image courtesy of Caspar Ammann
Cirrus Clouds
image courtesy of Lisa Gardiner
2. Cirrostratus (Cs): are thin, generally uniform clouds, composed of ice-crystals, capable of forming halos. When thick enough to be seen, they are whitish, usually with no distinguishing features.
Cirrostratus (Cs)
Cirrostratus Clouds
This is an image of cirrostratus clouds. You can see the sun through these clouds, as well as a big halo or circle around the sun.
Image courtesy of NOAA’s National Weather Service
3. Cirrocumulus (Cc): are high-altitude clouds, usually occurring at 16,000-40,000 feet. Like other cumulus clouds, cirrocumulus clouds signify convection. Unlike other cirrus clouds, cirrocumulus include liquid water droplets, although these are in a supercooled state.
Cirrocumulus Clouds: Sometimes they are made up of groups of small, rounded puffs (like the clouds in this image), and sometimes they appear in long, parallel bands.
Image courtesy of the UCAR Digital Image Gallery
Cirrocumulus Clouds: sometimes they appear in parallel bands like these clouds. This is also called a "mackerel sky" because the clouds look like the scales of a mackerel fish.
Image courtesy of the UCAR Digital Image Gallery
4. Contrail: (or vapour) trails are visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets. If the air is cold enough, this trail will comprise tiny ice crystals.

Contrails of plane
D. Extreme-level
Nacreous: Polar stratospheric clouds (PSCs), also known as nacreous clouds, are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 metres (50,000–80,000 ft). They are implicated in the formation of ozone.
Arctic stratospheric cloud (nacreous clouds)

Seen over Norway Foto:Mathias Midbøe
2. Noctilucent: Noctilucent clouds, also known as polar mesospheric clouds, are cloud-like phenomena in the upper atmosphere, visible in a deep twilight. They are the highest clouds in the Earth`s atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometers (47 to 53 mi). They are the highest clouds in the Earth`s atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometers (47 to 53 mi).

Polar mesospheric cloud
E. Vertical
Cumulonimbus (Cb): is a type of cloud that is tall, dense, and involved in thunderstorms and other intense weather. It is a result of atmospheric instability.
Cumulonimbus (Cb)
Cumulonimbus (Cb)
III. Causing the phenomena


Cirrus clouds produce hair like filaments made of the heavier ice crystals that precipitate from them. These "fall streaks", a form of virga
Nimbostratus is a sign of steady moderate to heavy precipitation.
Stratus clouds do not usually bring heavy precipitation, although drizzle and snow may occur, bring much lighter precipitation (drizzle) than nimbostratus
Altostratus clouds often are seen preceding a cold front, and their presence on a warm, humid, summer morning frequently signals the development of thunderstorms later in the day. Alto means high and these clouds may cause rain if they are higher up.
Cirrostratus clouds never bring precipitation.
Stratocumulus bring only light rain or snow, However, these clouds are often seen at either the front or tail end of worse weather, so may indicate storms to come.
Cumulonimbus can produce heavy rain.

There is evidence that the relatively recent appearance of noctilucent clouds, and their gradual increase, may be linked to climate change. Climate models predict that increased greenhouse gas emissions cause a cooling of the mesosphere, which would lead to more frequent and widespread occurrences of noctilucent clouds
There are many phenomena related to the clouds, but they are difficult to observe and discovery. And it is the mission of the scientist to help us understand more about these.
http://www.windows.ucar.edu/tour/link=/earth/Atmosphere/clouds/cloud_il.html
http://en.wikipedia.org/wiki
Some others.

Sources

Thanks for listening!
Designed by Ngo Dinh Khuong
K51-Meteorology